Many buildings are constructed of concrete panels which are precast and then assembled. In the precast manufacturing process, the concrete panels are normally cast flat in a mold, lifted from the mold and transported, usually in a horizontal orientation, and then assembled at a construction site.
In lifting the precast panels to transport, position and assemble the panels, the concrete panels are handled by external hoist or lift devices which engage anchors preset in the precast panels during manufacture of the panels. With reference to FIG. 9, an anchor A (usually four to eight per panel) is positioned by means of a plastic form PF and embedded in the cement forming a precast panel. After the cement cures (generally, the next day), the plastic forms are removed by breaking apart each form which leaves an open pocket with the uppermost portion of the anchor exposed in the pocket. The open pockets left in the concrete panels enable access to the anchors for attachment to a hoist or lift device. Once the concrete panels are in place at a site, these open pockets in the concrete panels then, for appearances sake, need to be filled or covered so that the wall surface is smooth and uniform.
One method of closing the open pockets in the precast concrete panels is to fill the openings with concrete or other material such as a drywall patching compound. However, this can be messy and difficult since the panels are in a vertical orientation once assembled and the fill material tends to flow out of the pocket or requires a second coat due to shrinkage on the first fill. Another method of closing the open pockets in the precast concrete panels is to position a cover therein or thereover. However, known covers have various shortcomings including being ill-fitting, and being prone to warping and relaxing under flexural stress by the material of the cover, whereby the cover then becomes loose in the pocket and can easily fall out of or be easily removed from the pocket. Many of these known covers are also constructed of a material that is weak, relaxes under pressure and does not allow paint to easily bond thereto.
The prior art discloses various recess or void filling devices. For example, U.S. Patent Application Publication No. 2004/0010985 A1 discloses a cover for use with concrete construction to cover a recess formed around an anchor embedded in the concrete. The cover includes a disk-shaped body to cover a recess to surround an anchor. First and second anchor engaging members extend from the body and receive the anchor therebetween. A plurality of fins are present on the anchor engaging members and have a height such that the fins positively engage the anchor. The fins are deformed to either resiliently or frictionally engage the anchor and thereby retain the cover in place over the recess.
U.S. Pat. No. 4,325,575 discloses a sealing plug which is inserted into a recess in a concrete slab once the hoist coupling used to lift the slab is removed. The plug includes a disk-shaped top and a cylindric extension dimensioned for a snug fit in a passage. The top is described as being slightly larger in diameter than the opening in the concrete slab.
U.S. Pat. No. 5,528,867 discloses a cover to be placed over a rod or hook embedded in a precast concrete block. The cover engages the rod or hook during transportation, manipulation and after installation of the block. The cover is of high density polyethylene and includes a platter and a vessel with a continuous sidewall. An internal hollow pocket is provided by the sidewalls. At least one slit is present in a vertical wall of the vessel. A cover member mates with a concrete wall and mechanically engages the rod or hook that extends out of the precast concrete block. The cover allows for movement of the block while the cover remains in place.
U.S. Pat. No. 4,386,486 discloses a cover plate for recesses in wall slabs. The cover plate includes a pair of peripheral pins which fit in passageways of a connector plug. The plug is attached to an anchor insert. The plate and pins can be molded as one piece and of plastic. The plate is stated to be large enough to cover the recess in the slab.
Japanese Published Application No. 06-341226 A discloses a core for embedment in concrete. The core includes a cover member fitted to the open end of the core so as to be flush with the concrete. The cover, on its underside, is shown to include four downward projections wherein two are inserted inside a female screw hole and two encompass the outside of the screw hole.
U.S. Pat. Nos. 6,460,824 B1 and 6,755,385 B2 disclose a void former and a cover used in casting a concrete block. The void former is attached to an anchor. The cover is attached to form work prior to casting. The cover includes pegs. These pegs align with bores in the void former to attach the void former to the cover. The concrete is then poured and allowed to harden. The cover is then removed.
Also known are various inserts or void-formers which are embedded in concrete including U.S. Pat. Nos. 3,298,148; 3,873,147; 4,068,879; 4,139,228; 4,179,151; 4,383,674; 4,383,675; 6,092,849; 6,334,286 B1; 6,550,834 B2; 6,688,049 B2; 6,694,680 B2; and 6,779,312 B2; and U.S. Patent Application Publication Nos. 2003/0140575 A1; 2003/0140576 A1; 2004/0168375 A1; and 2004/0044805 A1.
Also known are various void formers, recess plugs and prefabricated building panels including U.S. Pat. Nos. 4,157,640; 4,807,843; and 6,568,730 B1; and U.S. Patent Application Publication No. 2004/0012216 A1.
These known devices all have various shortcomings including being ill-fitting in a pocket, are prone to warping, prone to loss of strength under stress, easily removed from a recess in a precast concrete panel and poor adhesion of paint thereto. These and other shortcomings of these devices are addressed by the present invention.